public void button2_Click(object sender, EventArgs e) // Retrieve Button on click event
{
// selecting or typing a valid order id and displaying the results
try
{
int orderID = Convert.ToInt32(cborderId.Text);
Orders myOrder = OrdersDB.GetOrders(orderID);
List <OrderDetails> myOrderDetails = OrderDetailsDB.GetOrderDetails(orderID);
if (Object.Equals(myOrder, null)) // if ordr id not valid, show the follofing message
{
MessageBox.Show("No matching Order Id's found, please provide a valid Order ID", "Order ID Error");
}
else // else display all the fields and read only order details data grid form
{
displayOrder(myOrder);
displayOrderDetails(myOrderDetails);
calculateTotalprice();
}
}
catch (FormatException) // catching the wrong format order id exception, in case user types an alphabet or anything other than the valid id
{
MessageBox.Show("Select from the drop down list and Retrieve.", "Input Error");
}
}
private void calculateTotalprice() // calculating the total price for all the orders associated with one order id
{
int orderID = Convert.ToInt32(cborderId.Text);
List <OrderDetails> myOrderDetails = OrderDetailsDB.GetOrderDetails(orderID);
double totalPrice = 0;
double UnitPrice = 0;
int Quantity = 0;
double Discount = 0;
foreach (OrderDetails d in myOrderDetails) // calculating by going through each order details rows
{
UnitPrice = d.UnitPrice;
Quantity = d.Quantity;
Discount = d.Discount;
totalPrice += UnitPrice * (1 - Discount) * Quantity;
}
lblTotalPrice.Text = totalPrice.ToString("c"); // displaying the result in the text field in a currency format
}